Sales of head lice prevention and treatment products have increased by 30% in the past seven days.

Careplus Pharmacy say the spike coincides with the end of summer holidays, and the return to school for hundreds of thousands of pupils across Ireland.

Head lice are tiny insects that are the size of a pencil tip when they hatch, but which can grow up 3mm long.

They move by climbing from person to person.

Waterford pharmacist Liz Murray says: "Since the schools reopened, we have seen a lot of stressed parents seeking out treatment for head lice.

"People need to realise that it's never a reflection on the hygiene of a child, as head lice can affect anyone."

Head lice and nits are seen on a scalp | Image: Britta Pedersen/dpa-Zentralbild/dpa

"While many people tackle the issue with a traditional lice comb, there are a number of medicated lotions and sprays that can help.

"The most important thing to do is to use the treatment properly, and repeat as instructed after seven days.

"This helps minimise the risk of the return of the lice".

When using a lice comb, parents are advised to wash the hair first and methodically comb the hair from top to bottom

They should also check for baby lice hatching from eggs three to five days after product has been used.

Murray says a regular routine will help.

"It’s a good idea to do weekly head checks, especially in the 'hot spots'.

"These are the back of the neck, behind the ears, and part lines.

"Be careful not to mistake a louse for dandruff, dirt or product for a nit. Remember, if you can blow it away, it's not a nit".